According to the World Health Organization (“WHO”) and the United Nations Children's Fund (“UNICEF”), diarrheal diseases cause 12 percent of deaths in children under the age of 5, worldwide. The leading contributor to diarrheal diseases is drinking water contamination. Over 1 billion people have no access to clean water sources and as many as 2.5 billion have no basic sanitation. The WHO estimates that gastroenteritis, which is a diarrheal disease of the intestinal tract, causes 5 to 10 billion cases of disease and 3 to 5 million deaths annually worldwide, 2 million of which are children. Bacteria, viruses, and parasites are frequent pathogens that cause diarrheal diseases and are able to infect large populations through the contamination of drinking water. Additionally, many of the life cycles of these organisms require the individual to ingest the water, not only to infect the individual, but to also spread the disease.
According to some, a leading cause of infection from these pathogens is from secondary contamination of water at the point-of-use (e.g. the home). Some people in the industry believe that household based disinfection systems are twice as effective for preventing diarrheal diseases as source based disinfection systems, due to the increased likelihood that the source based treated water can become contaminated during transport back to the point-of-use or due to unsanitary use after transport.
Ultraviolet (“UV”) light is currently used in a number of commercial, medical, and home applications for disinfecting surfaces, clothing, liquids, etc. Specifically, water disinfection is commonly needed throughout many industries. UV light is light in the ultraviolet light spectrum ranging from 100 to 400 nanometer (“nm”) wavelengths. The utilization of UV light for disinfection can be done on a small or a large scale though different power sources. Small scale applications include, for example, hand-held devices for keyboards using battery power. Alternatively, large scale applications include utilizing UV light disinfection with electric power, as is the case for water treatment plants.
UV light kills organisms acutely or as they try to replicate, by destroying the nucleic acids contained in the various organisms. Water-related diseases are classified into 3 major groups: waterborne diseases (ingestion=infection), water-washed diseases (inadequate clean water for hygiene use), and water-based diseases (microorganisms live in contaminated water and penetrate skin) UV light for disinfection, specifically utilized at the point-of-use, can have a huge impact on completely eliminating or significantly reducing the following types of diseases, to name a few:
OrganismImpactWaterborne DiseasesCholeraVibrio choleraePandemic risks, 25-50% mortalityTyphoidSalmonella typhi17 million cases in 2000Salmonellosisother Salmonella1.4 million cases in U.S. annuallyDysenteryShigella600,000 deaths/yr < age 5 yrsE. histolytica100,000 deaths/yr, 480 million casesCryptosporidiosisCryptosporidium17% of all childhood diarrheaGiardiasisGiardia lamblia30% prevalence in tropicsHepatitisHepatitis A42,000 cases in 2005DiarrheaETEC (E. coli)20% of all diarrheal casesY. enterocoliticaFood and WaterborneCampylobacterFood and WaterborneBalantidium coli80% asymptomatic carriersNorwalk virusSeasonal epidemicsRotavirus#1 killer of children from diarrheaAstrovirusesWorldwide distributionWater-Washed DiseasesGuinea wormDracunculus medinensis55,000 cases worldwideTrachomaChlamydia trachomatisWorld's leading preventable cause ofblindness. Nearly 10% of the globalpopulation at risk.ScabiesSarcoptes scabeiChronic skin infection in over 300million people worldwideWater-Based DiseasesSchistosomiasisS. ovale, S. japonicum200 million infections annually andS. haematobium280,000 deaths/yr.
The Millennium Development Goals (MDGs) accorded in the Millennium Declaration (2000) by the United Nations seeks to provide clean water and basic sanitation to over 600 million people by the year 2015. Cost estimates for the required investment to reach the MDG goal are in the rage of $11.3 billion per year in clean drinking water (and sanitation), which is estimated to yield an annual return of nearly $84 billion per year. It is necessary to develop systems and methods to provide clean water to large populations at the point-of-use in remote areas.